Storage and retrieval of information during learning is analyzed in normal control subjects and neurosurgical patients with indwelling therapeutic electrodes in the thalamus or temporal lobe. Visual and auditory memory tests provide the behavioral measures. Average evoked potentials are computed with special reference to participation of different brain systems during perception, learning and subsequent recall. Neuropsychological disabilities effected by neurologic diseases are also analyzed and compared with aberrant behavior of psychopathologic patients.